Recent Change? /PAE with 32GB of hot swap RAM

[Guest Blunderdog]

For a little over a year we've run a cluster with Server 2003 32bit machines

with quad processors and 32 GB of hot swapable ram. According to

http://support.microsoft.com/kb/283037 the /PAE switch is not required in the

boot.ini for applications that can use the ram to get access to it. In this

case it is SQL 2000. We've run fine without that switch since September 2006.

Today we noticed these machine were only reporting 3.5 GB of RAM in system

manager. However when the machines boot the system clearly reports all 32 GB.

 

To fix the problem I added the /PAE switch and rebooted the passive node and

now Windows reports 32GB. Has something changed, perhaps a recent update,

that has changed or required this behavior. We last performed updates on

12/28.

[Guest Ryan Hanisco]

RE: Recent Change? /PAE with 32GB of hot swap RAM

 

Hi Blunderdog,

 

I have not seen any updates that would change this behavior. As it stands

the /PAE switch would not hurt you even if you didn't have hot-swappable

memory and I would include it to be sure that there was no confusion in the

memory space addressing. That being said, there are some possible

differences between hardware vendors and it is possible that there was a

detection issue with you specific server/ MB/BIOS/Memory configuration that

would not have it detect it as hot-swappable -- though I would have expected

this to have affected you all along, unless you just did BIOS updates.

 

If you are sure that you always had access to the memory (remember that the

boot declaration of memory is different from what the OS thinks it has) then

I would consider the situation highly suspect. I would go back through he

logs looking for BIOS or firmware updates and monitor the memory for issues.

If this is part of a cluster, I would consider taking the node offline and

running a memory diagnostic to be sure that there are no memory problems

lurking.

 

Other than that, I would leave the /PAE switch in and call it good.

--

Ryan Hanisco

MCSE, MCTS: SQL 2005, Project+

http://www.techsterity.com

Chicago, IL

 

Remember: Marking helpful answers helps everyone find the info they need

quickly.

 

 

"Blunderdog" wrote:

> For a little over a year we've run a cluster with Server 2003 32bit machines

> with quad processors and 32 GB of hot swappable ram. According to

> http://support.microsoft.com/kb/283037 the /PAE switch is not required in the

> boot.ini for applications that can use the ram to get access to it. In this

> case it is SQL 2000. We've run fine without that switch since September 2006.

> Today we noticed these machine were only reporting 3.5 GB of RAM in system

> manager. However when the machines boot the system clearly reports all 32 GB.

>

> To fix the problem I added the /PAE switch and rebooted the passive node and

> now Windows reports 32GB. Has something changed, perhaps a recent update,

> that has changed or required this behavior. We last performed updates on

> 12/28.

[Guest Blunderdog]

RE: Recent Change? /PAE with 32GB of hot swap RAM

 

I will check to see if bios upgrades were done recently. That is not out of

the question since I know some HBA updates and other stuff was done recently

as well. If so then that will be the explanation.

 

The full 32 GB of RAM had been showing in both the OS, BIOS and SQL since we

got it all configured properly. We just noticed yesterday that this was no

longer the case.

 

I like your plan, for now, the /PAE switch has restored things to normal. I

got all nodes rebooted last night.

 

"Ryan Hanisco" wrote:

> Hi Blunderdog,

>

> I have not seen any updates that would change this behavior. As it stands

> the /PAE switch would not hurt you even if you didn't have hot-swappable

> memory and I would include it to be sure that there was no confusion in the

> memory space addressing. That being said, there are some possible

> differences between hardware vendors and it is possible that there was a

> detection issue with you specific server/ MB/BIOS/Memory configuration that

> would not have it detect it as hot-swappable -- though I would have expected

> this to have affected you all along, unless you just did BIOS updates.

>

> If you are sure that you always had access to the memory (remember that the

> boot declaration of memory is different from what the OS thinks it has) then

> I would consider the situation highly suspect. I would go back through he

> logs looking for BIOS or firmware updates and monitor the memory for issues.

> If this is part of a cluster, I would consider taking the node offline and

> running a memory diagnostic to be sure that there are no memory problems

> lurking.

>

> Other than that, I would leave the /PAE switch in and call it good.

> --

> Ryan Hanisco

> MCSE, MCTS: SQL 2005, Project+

> http://www.techsterity.com

> Chicago, IL

>

> Remember: Marking helpful answers helps everyone find the info they need

> quickly.

>

>

> "Blunderdog" wrote:

>

> > For a little over a year we've run a cluster with Server 2003 32bit machines

> > with quad processors and 32 GB of hot swappable ram. According to

> > http://support.microsoft.com/kb/283037 the /PAE switch is not required in the

> > boot.ini for applications that can use the ram to get access to it. In this

> > case it is SQL 2000. We've run fine without that switch since September 2006.

> > Today we noticed these machine were only reporting 3.5 GB of RAM in system

> > manager. However when the machines boot the system clearly reports all 32 GB.

> >

> > To fix the problem I added the /PAE switch and rebooted the passive node and

> > now Windows reports 32GB. Has something changed, perhaps a recent update,

> > that has changed or required this behavior. We last performed updates on

> > 12/28.